1. Field of the Invention
The present invention relates generally to internal combustion engines having exhaust gas recirculation (EGR) systems, and more particularly, to an internal combustion engine having an EGR system and a integral air brake compressor supply fitting downstream of the turbocharger compressor and upstream of where the exhaust gas is introduced into the EGR mixer.
2. Description of the Related Art
Turbochargers for gasoline and diesel internal combustion engines are known devices used in the art for pressurizing or boosting the intake air stream, which is then routed to a combustion chamber of the engine to improve engine performance. Turbochargers achieve boost by using the heat and volumetric flow of exhaust gas exiting the engine to drive a turbine that in turn powers a compressor for the intake air stream.
Air brakes are also known devices in the braking systems of heavy vehicles. Air brakes require a supply of pressurized air from a compressor to operate. Air brake compressors for heavy vehicles currently receive their air supply from the intake manifold of the internal combustion engine in order to take advantage of the already boosted air pressure. However, in order to meet pending emissions regulations, many engines will require recirculation of the exhaust gas back to the engine intake manifold.
Exhaust gas recirculation (EGR) is a known method for reducing NOx emissions in internal combustion engines. A conventional EGR system comprises a control valve that regulates the amount of exhaust gas that is taken from an engine exhaust manifold and returned to an engine induction system for mixing with the intake air, and subsequent combustion.
For present engine configurations, an EGR system eliminates the intake manifold as a source of clean compressed air. If exhaust gas is allowed to enter the air brake compressor, the compressor will become fouled, seriously affecting brake performance and vehicle safety.
Consequently, a need exists for an improved system that allows the air brake compressors to continue to take advantage of the boosted air pressure, while simultaneously allows for EGR such that the necessary emissions regulations are satisfied.